HSC308 Exam 5 Questions with All Correct Answers
Neural Factors - Answer- Normal age related changes:
• Reflexes slow with age
• Motor unit activation decreases with age
- Decrease building of neurons in the brain
- Nearly 40% decline in a number of spinal cords axons and a 10% decline ...
HSC308 Exam 5 Questions with All
Correct Answers
Neural Factors - Answer- Normal age related changes:
• Reflexes slow with age
• Motor unit activation decreases with age
- Decrease building of neurons in the brain
- Nearly 40% decline in a number of spinal cords axons and a 10% decline in nerve
conduction velocity
- Decrease in muscle action time and decreased stimulus to process information to
produce response
- Reduced force production
- Affects reaction, coordination, and movement
Reduced Aerobic Capacity w/Aging - Answer- - VO2 max decreases after college age
about 1% per year
- Habitual physical activity exert greater influence on aerobic capacity
- older adults who have high aerobic fitness demonstrate lower large elastic artery
stiffness and better cognitive performance compared to age-matched sedentary adults
with low aerobic fitness.
- Aging is also associated with reduced cognitive function, cerebrovascular reactivity
- The longitudinal rate of decline in peak VO2
-Numerous cross-sectional studies have demonstrated a decline in peak VO2 of 5% to
10% per decade in untrained individuals
- physical activity declines with age
Activity Level & Aging - Answer- - Physical activity declines with age
-Older individuals who maintained high levels of physical activity for two years following
an aerobic exercise intervention demonstrated increased bilateral dorsolateral prefrontal
cortex activation in response to processing speed tasks
- high volumes of low intensity physical activity may reduce age-associated increases
- greater aerobic fitness is a predictor of brain health in aging populations, with higher
levels of fitness associated with greater white matter integrity
- higher levels of physical activity to be associated with better cognitive performance
Muscle Physiology & Aging - Answer- *Normal age associated changes*:
• Reduction in oxidative enzymes
• Reduction in capillary density
*Exercise Training*:
• Oxidative enzymes only mildly reduced
• Capillary density is maintained
, Decreased capacity for oxygen delivery/utilization
• Capillary rarefaction. Capillary-to-fiber ratio decreases and increased atrophy
• Reduced mitochondrial oxidative capacity?
Sarcopenia: characterized by losses of both muscle fibers, particularly of type 2 and
fiber area
- Decrease in muscle protein mass
- Reduction in contractility
- Loss of neuronal innervation (possibly higher in Type II fibers innervated by large
alpha motor neurons)
Muscle Fiber and Aging - Answer- Type II fiber loss and type I fiber
gains with aging
- Decrease in type II motor neurons
- Type I neurons innervate old type
II fibers?
- Higher percent type I fibers
--Selective denervation of muscle fibers, particularly in Type II fibers
-- Fiber death
----Muscle fiber types tend to cluster with similar fiber types
- Increase in acidosis, which leads to muscle wasting
- Fiber loss begins around the 50 through the age of 80
- Moderate resistance can slow the process down as older men demonstrate greater
absolute gains in muscle gain
Cardiovascular Function & Aging - Answer- *Central changes*
• Reduced maximal HR (heart wall thickness increases modestly, due largely to an
increase in myocyte size)
• Maximal stroke volume (SV) decreases w/age
- Reduced contractility, response to catecholamines
- Partial loss of Frank-Starling mechanism
--------in older individuals
whose heart rate increase is less, increases in left ventricular volume and stroke volume
continue throughout exercise, an example of the Frank-Starling mechanism.
- LV, arterial stiffening
• VO2 max decreases with age due to decreased Qmax
- Due more to decreased HR max, less to decreased SV max
- Changes in body weight and decline in maximal oxygen uptake (VO2max)
-A lower stroke volume, heart rate, and arteriovenous oxygen difference at maximal
exercise all contribute to the age-related decline in VO2max
-maximal cardiac output and stroke volume normalized to fat-free mass were greater in
men than in women
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